Postharvest curing and storage of New Zealand-grown potato cultivars (‘Moonlight’ and ‘Nadine’) for the fresh export market

ABSTRACT

Tuber quality problems such as skin tears (skinning), rots, browning, shrivelling and weight loss in New Zealand-grown export potatoes have caused significant postharvest losses and insurance quality claims from overseas distributors. These quality issues could be attributed to poor management of curing and subsequent storage conditions. This study investigated the effects of various curing and storage conditions (i.e. duration, temperature and relative humidity (RH)) on tuber quality of two potato cultivars, ‘Moonlight’ and ‘Nadine’, that are exported to Fiji. Results have shown that high curing RH (93%) led to significantly lower skin browning, shrivelling and weight loss in both cultivars, and significantly lower tuber rot in ‘Nadine’ than low curing RH (62%). Shorter curing duration (7 days) yielded significantly lower shrivelling in ‘Moonlight’, and significantly lower tuber rot in ‘Nadine’, than longer curing duration (14 days) or control (0 day). Percent weight loss was significantly lower in cured potatoes than in control for both cultivars. Curing temperatures (16 or 26°C) and storage RH (65 or 90%) did not significantly affect the tuber qualities assessed. Therefore, 7 d curing at >90% RH and at least 15°C is recommended for minimising quality problems occurring during transport of these potato cultivars to distant markets.

KEYWORDS:

• Solanum tuberosum
• relative humidity
• skin browning
• suberisation
• temperature
• weight loss

Acknowledgements

We wish to express our gratitude to Iain Kirkwood, Technical Manager of Potatoes New Zealand (PNZ), for providing valuable information which helped us plan and design the experiment, and for coordinating with potato growers, Paul Olsen and Iain Corbetts, to whom we are grateful for supplying the potato tubers we needed to run the experiment successfully; and to the entire Massey AgriFood Digital Lab (MAFDL), led by Professor Andrew East, for all the support in establishing and running the trial smoothly.

Disclosure statement

No potential conflict of interest was reported by the author(s).